Sky Tower | A 108-story luxury mixed-use residential complex where South Korea's top elites live. It features various indoor facilities and was hosting a grand anniversary party. The structure is divided into two towers, connected by a bridge around the 60th floor.

Plot Summary | On Christmas that year, despite severe turbulence and strong gusts, Chairman Jo forces a helicopter event against staff opposition. A helicopter crashes into the Riverview building, sparking a massive fire that traps many people inside.

• Issues with Sky Tower -

1. Poor Kitchen Ventilation | There are too few vents compared to the number of stoves, leading to poor air circulation.

2. Sprinklers | The pipes supplying water to the sprinklers on floors 60–80 froze and burst due to the cold weather, making them useless. The pipes, originally inside the columns, were moved to the stairwell to expand commercial space. In this case, they should have been wrapped in insulation, but no such measures were taken at Sky Tower.

3. Refuge Areas | A major catastrophe occurred because emergency elevators and refuge safety zones were not installed.

Story Progression | It is Christmas Eve. The beginning of the movie shows Seoul with the Han River in the background and the appearance of Sky Tower. Dae-ho and his daughter Ha-na wake up, and Dae-ho promises Ha-na the best Christmas ever.

The Food Mall at Sky Tower is busy preparing for the Christmas party, during which a small fire breaks out in the kitchen due to a mistake by In-geon. Fortunately, the fire is extinguished, but the manager is furious. Then, Dae-ho, the facilities management team leader, appears and points out a problem with the sprinklers, holding a lighter to one. Water sprays everywhere, making a fool of the manager. Yoon-hee flirts with Dae-ho, thanking him for the help.

Dae-ho has to go to work because of the sprinkler issue, making Ha-na pout. Dae-ho explains it's to keep people safe, but Ha-na says it's always like this and nothing changes. Dae-ho's friend, watching nearby, asks if he can't even comfort a child and whispers something to Ha-na, who suddenly bursts into tears. As Dae-ho tries to comfort her, Yoon-hee runs over to ask what's wrong and soothes the child.

Dae-ho's friend says they have to go quickly because of the sprinklers and asks her to watch the child before hurriedly leading Dae-ho away. Dae-ho only manages to tell Ha-na to listen to Yoon-hee before following his friend. On the way down in the elevator, Dae-ho asks again why he made the child cry. His friend laughs and says Ha-na should be an actress when she grows up. He told her to just cry if she wanted to be with Yoon-hee, and she actually did it. He added that it's Ha-na, not Dae-ho, who needs to win Yoon-hee over.

At that time, at the Yeouido Fire Station, rescue workers are engrossed in a card game when the alarm suddenly rings. They quickly pack up and prepare to head out, but it turns out to be an emergency drill, not a real situation. Byeong-man, the slacker, is frustrated that a good game was ruined when he encounters a man asking for the chief's office. His name is Seon-woo, a rookie who just graduated from the Fire Academy.

After reporting his arrival to the center chief, Seon-woo follows his senior, Byeong-man, to the duty room. Byeong-man tells him to get undressed and prepare for a shower. When a confused Seon-woo asks why, Byeong-man asks, "How would you feel if your bride came to you on your wedding night without showering?" Seon-woo retorts, "That would mean she's not prepared for the wedding night." Byeong-man says it's the same thing—Seon-woo isn't prepared to receive his first equipment—and tells him to go wash. The naive rookie takes him literally and starts showering immediately. Byeong-man sits outside the shower door and lectures, "Firefighters who have the three essential qualities are extremely rare. I am one of those rare firefighters. Since you're under me, you will become a true firefighter."

Just then, the alarm rings, and Byeong-man tells him to prepare for dispatch before rushing out. However, Seon-woo is completely naked and covered in soap suds. He has no choice but to rush out, covering himself with only a plastic bowl. He runs into a cleaning lady on the way, but she doesn't even blink at the sight of the naked Seon-woo. His senior yells for him to get his gear on and hurry, and Seon-woo follows. But when he catches up, all the firefighters are waiting with cake, drinks, snacks, and Seon-woo's gear. It was a surprise initiation ceremony. They all sing a song to welcome him, and though initially flustered, Seon-woo soon enjoys it.

Young-ki, an elite firefighter known as a legend at the academy, takes the 25th off to spend his first Christmas after marriage with his wife. He stops by a bakery to buy a cake and goes to the duty room. When he arrives, the resting members all fix their eyes on him. When Young-ki opens his locker, it is covered in supportive notes telling him to have a cozy Christmas with his wife. Young-ki smirks and looks back at the members, who quickly pretend to be busy.

Back at Sky Tower, Chairman Jo forces the artificial snow event using fire helicopters despite warnings that it's dangerous due to gusts. When he hears the Disaster Management Agency plans to cancel the helicopter permit, he contacts the Mayor of Seoul to get support. Thus, on Christmas Eve evening, several helicopters equipped with snow machines begin flying around Sky Tower, spraying artificial snow. They succeed in drawing people's attention, but the trouble starts there.

The building wind around Sky Tower was exceptionally strong that day, and one helicopter caught in an updraft begins to shake precariously. Min-jeong, who was receiving a proposal from In-geon inside an observation elevator, witnesses this and is horrified. In-geon also sees it just as he is about to hand over the ring.

The shaking helicopter collides with another, breaks through the glass ceiling of the sky bridge and Elder Kim's window, and then smashes through the building's glass, piercing multiple floors of the Riverview building before crashing into the computer room (63rd floor). The snow machine gets lodged in the building and then falls, crushing a city bus below. Meanwhile, the entire building shakes, and as glass shards and fixtures fall throughout the interior, people begin to evacuate in a panic. The Christmas party that should have been happy turns into a scene of carnage for survival. The helicopter in the computer room is shattered, the pilot is dead, and fuel leaks from the wreckage, sparking a fire throughout the building. Dae-ho, who was outside, thinks of Yoon-hee and Ha-na and runs back inside.

A fire report is received at Yeouido Fire Station, and the members prepare to head out. Young-ki tries to join, but Byeong-man stops him, telling him to prioritize his wife today. He hesitantly agrees, but feeling guilty about partying while his subordinates fight a fire, he chases the departing fire truck, climbs on, and orders a Regional Level 1 response. Byeong-man sighs but knows it's impossible to stop his passion for firefighting. A moment later, Young-ki, now fully geared, calls his wife to say he'll be a little late and hangs up quickly.

Meanwhile, people on the lower floors of Sky Tower could escape quickly via stairs and escalators, but those on the upper floors all flock to the elevators, turning the area into a battlefield for survival. The control room is broadcasting a ban on elevator use, and Dae-ho's friend scolds a staff member for not broadcasting it, only to be told that the broadcasts are ongoing but people are still swarming. Looking at the monitors, every elevator lobby is a chaotic mess of people. Hearing this, Dae-ho's friend sighs and runs off somewhere.

Yoon-hee, on the 67th floor, tries to escape via the emergency stairs with Ha-na, but the exit is already a sea of fire. She ends up running to the elevator with Ha-na on her back, but the lobby is in chaos with the crowd. Only one security guard is guarding the elevator, and his behavior is appalling. Instead of stopping people from using the elevator, he actively encourages it, shouting for order while leading the way.

A moment later, the elevator doors open, and people scramble inside. The guard tells them to move back so it can go down and come back up quickly. Yoon-hee approaches, saying there's a child here, but the guard pushes her aside, asking where there's room for children in this situation. When the weight limit alarm rings, he pulls out a cleaning lady who had boarded first, gets in himself, swipes his staff card, and starts the elevator. Yoon-hee pleads to at least take the child, but the doors close.

The elevator, which seemed to be descending fine, soon stops with a violent vibration and is engulfed in flames rising from below. The guard inside smells something strange and looks down to see his rubber soles melting like cheese. Before his scream even ends, the elevator melts in the flames, and everyone inside dies as it explodes. Standing outside, Yoon-hee sees flames passing through the elevator door gaps, screams for people to get back, and moves away. The explosion causes casualties, but fortunately, Yoon-hee and Ha-na are only knocked over by the blast. Seeing this on the CCTV, Dae-ho rushes out of the control room to find them. Dae-ho's friend also falls to his death in an elevator shaft after being unable to escape due to falling debris while helping people.

As the fire spreads rapidly, Dae-ho enters the fire zone to find Ha-na and Yoon-hee. Young-ki, having just arrived, moves up to the 19th floor with Seon-woo via an aerial ladder while other members run toward the ignition point. As they try to enter the area near the ignition point, Young-ki senses a fire-induced explosion, yells for the members to run, and bumps into Dae-ho while evacuating. Young-ki saves Dae-ho through the explosion and evacuates to the emergency stairs with the team. Dae-ho joins the firefighters to reach the ignition point, but the path is cut off. There is a detour, but it would take over 5 minutes. Dae-ho identifies himself as the facilities manager and asks if they can break through a wall to reach the server room directly. The team breaks through, and Young-ki uses Byeong-man's oxygen tank to blow up the helicopter at the ignition point, successfully suppressing the fire around the server room.

Meanwhile, Chairman Jo enters the tower control room and asks if the fire is under control. Staff say the fire in the computer room where the helicopter hit is out. Chairman Jo then orders the firewalls to be lowered. Staff warn that people haven't escaped yet, but Chairman Jo activates the firewalls anyway, trapping many people. Just before the firewall closes, Dae-ho enters the Chinese restaurant and reunites with his daughter Ha-na. He radios Kang Young-ki, telling him many people are trapped in the restaurant and asking for rescue.

While Young-ki and the team are heading to the restaurant, the Fire Commissioner radios that there is a much more urgent situation with dozens of people suffering from breathing difficulties. Consequently, Young-ki orders Byeong-man to go to the restaurant alone to set explosives on the firewall while he rushes to the other scene with the rest of the team. Instead of an emergency, they find a Congressman (Park Jeong-hak) and his wife sitting calmly, shouting about why they took so long. He hesitates when the wife looks for her baby, but the "baby" turns out to be a dog. Realizing he abandoned people in danger just to save a Congressman and a dog, Young-ki vents his anger over the radio to headquarters. He tells one firefighter to evacuate these people and heads back to the restaurant with the rest.

In the meantime, Manager Cha is banging on the firewall, complaining about the firefighters' delay, when cracks begin to appear in the floor. The reinforced concrete melts due to the high heat, and the building begins to collapse. Oh Byeong-man arrives and starts setting explosives on the firewall outside. The people inside the restaurant, realizing this, bang on the door fearing the floor will collapse entirely if the explosives go off, but Byeong-man doesn't hear them. Eventually, the floor gives way, and Byeong-man falls to the floor below. At that time, an expert at headquarters warns that the steel structure is exposed due to spalling and that 'the steel may bend like taffy if exposed to high heat for a long time.' The center chief says that's impossible so soon, but the expert explains that 'high-strength concrete undergoes spalling faster than normal concrete.' Meanwhile, the people in the restaurant try to escape using an external maintenance gondola. Old Man Yoon reassures a terrified Mrs. Jeong and pushes her to jump into the gondola, then dies in an explosion. The gondola drops slightly from the impact, and Lee Dae-ho says they 'must go back inside the building.' They swing the gondola like a pendulum to break a window and re-enter, but Mrs. Jeong fails to disembark in time and falls to her death.

Meanwhile, Oh Byeong-man, who fell to the lower floor, moves along and meets Elder Kim's group praying fervently in a pool. Meanwhile, Manager Cha asks Dae-ho, who is trying to open an emergency door, where he's going. Dae-ho says if they go up a few floors, they can evacuate to the adjacent building via the sky bridge. At the same time, Rescue Captain Kang Young-ki and Lee Seon-woo see the sky bridge from outside and rush to the scene, meeting Dae-ho's group. However, because the helicopter impact on Building A damaged the bridge, Young-ki warns Dae-ho's group that 'the bridge might collapse if too many people cross at once.' Young-ki and Seon-woo place fluorescent markers on the bridge and tell people to only step near the markers and never run. Ha-na crosses first, followed by a pregnant woman. Manager Cha tells the pregnant woman to hurry, but soon, panicked by the sound of the building collapsing, he runs on the bridge, the glass floor breaks, and he falls to his death.

Seon-woo and Ha-na, who escaped to the adjacent building, leave via helicopter from the roof. Riverview succeeded in delaying the collapse by releasing water from the tanks, but the building continues to tilt. As the situation worsens, EOD is deployed for a controlled demolition. A firefighter tells Young-ki that the demolition team is in and members are withdrawing, urging him to get out quickly. Elder Kim asks if the fire wasn't put out with water earlier, but Young-ki says they only bought time to escape. EOD begins setting bombs on the building.

The group takes a freight elevator to withdraw. Dae-ho says Sky Tower has automatic braking systems every 10 floors that will catch the elevator if it falls, but Byeong-man scoffed, asking how the brakes could be intact when the walls are collapsing from spalling. Yoon-hee asks if it's a problem even if it works—what if they stop in the middle of the fire? However, Young-ki agrees with Dae-ho, saying that since the brakes won't be intact in this fire zone as Byeong-man said, they can pass through at high speed, and if the brakes catch just once at the 20th or 10th floor, they can get out. With no other alternative, they decide to move, and the firefighters board the elevator after setting the bombs.

The elevator shakes briefly from the explosion, but they board safely and close the doors. Upon pressing the detonator, the elevator begins to plummet along with the explosion. The descending elevator stops on the 37th floor, which happens to be a fire scene. Seeing the flames through the door gaps, Byeong-man tells people they must go down and starts jumping in place; the others catch on and jump with him. Thanks to this, the stalled elevator starts falling at high speed again. Contrary to what Dae-ho and Young-ki said, it doesn't stop after 10 floors and barely manages to stop at the 5th floor. However, only Young-ki, Dae-ho, and the pregnant woman make it out safely before the elevator plummets. Young-ki and Dae-ho decide to go back to save the others.

Young-ki, Dae-ho, and Seon-woo enter to blow up the rainwater storage tank and escape with the remaining people. After meeting the survivors, the three move to blow up the tank, but Young-ki loses the remote during the move. Having lost the remote, Young-ki volunteers to sacrifice himself and manually detonates the rainwater storage tank. The explosion allows Dae-ho's group to escape through the Han River, and Riverview is demolished. The movie ends with scenes of Young-ki's wife sobbing after hearing of his death from Byeong-man, In-geon hugging Gil-su's son, the cake Young-ki reserved for 7 PM, and finally, the surrounding area after Riverview's collapse.

(However, Guest can change the fate of the characters.)

• Other Characters -

Kang Seung-joo | Male. Chief of the Yeouido 119 Safety Center (Fire Captain). Arrives on the scene and commands firefighters from outside.

Lee Seon-woo | New recruit of the 119 Rescue Team at Seoul Yeouido Fire Station, rank of Firefighter. He undergoes a harsh initiation and equipment ceremony... but from his first day, his first dispatch becomes the worst disaster in history. He tries to cross to the non-burning side via the sky bridge with Kang Young-ki, but the bridge collapses. He takes care of Dae-ho's daughter Ha-na and escapes to the roof. He puts Ha-na on a fire helicopter and is led by his senior to escape on it himself. Later, he re-enters with Kang Young-ki and Lee Dae-ho to blow up the septic tank, witnessing Kang Young-ki's sacrifice firsthand.

Chairman Jo | Owner of Sky Tower and corporate CEO. The root of all evil who caused the Sky Tower disaster by pushing for the artificial snow event despite extreme weather. He hosts a grand party at Sky Tower every Christmas. A man who takes risks to show off the majesty of the tower he spent his life on. His planned helicopter event almost gets canceled due to worsening weather, but desperate to show off the glamour of Sky Tower, he ignores staff warnings and gets illegal approval from Seoul City Hall to use helicopters for the snow event. While forcing the party to proceed, a helicopter crash causes a catastrophe at Sky Tower. He escapes but remains silent while watching the burning building.

In-geon | Works in the Japanese cuisine section of the Sky Tower kitchen. He bickers with the head chef. He hides a ring inside ice cream only for the manager to gobble it up, and his appearance peeling onions with tears and snot streaming down his face screams, 'I'm a comic relief character, I won't die, don't worry.' He proposes to his girlfriend in an elevator while it's snowing artificially, but the helicopter crash traps them inside. He barely escapes with the help of a passing pregnant woman and joins Seo Yoon-hee and others in the restaurant, eventually getting out somehow. He gets trapped underground due to the elevator fall but succeeds in escaping to the Han River through the water current. Later, he weeps while hugging the son of the head chef, who is holding a sign looking for his father.

Kim Gil-su | Head chef of the Japanese section at Sky Tower, forming a comedy duo with In-geon. When Ha-na and Yoon-hee visited the kitchen, he personally put a chef's hat on her and performed slapstick with pizza dough. However, he gets caught in the building collapse and is pinned under debris when he meets Young-ki and others. Since rescue is impossible, they only give him painkillers to temporarily dull the pain, and Young-ki and Seon-woo leave the spot. At the very end of the movie, In-geon sobs upon seeing his son looking for him.

Lee Ha-na | Lee Dae-ho's daughter. A typical precocious child. On the day of the Christmas party, she pouted at her dad for having to go fix the sprinklers, but after being told by her dad's friend to just cry if she wanted to play with Yoon-hee, she actually cried. She then had a fun time with Yoon-hee until the fire broke out, trapping her on the 67th floor. She eventually reunites with her dad, but panics when the sky bridge collapses while she is crossing. Lee Seon-woo barely manages to rescue her, but she is separated from her dad again. She succeeds in escaping via helicopter with Seon-woo and runs to hug Yoon-hee, who survived and made it out of the scene.